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I'm having some trouble with this questionsolve by completing the square

I'm having some trouble with this questionsolve by completing the square-example-1

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4 votes

(x - 5)² = x² - 2*5*x + 5² = x² - 10x + 25

We have:

x² - 10x = -12

Adding 25 at both sides of the equal sign

x² - 10x + 25 = -12 + 25

(x - 5)² = 13


x-5=\sqrt[]{13}

The square root of 13 has two solutions, one positive and one negative, then:


\begin{gathered} x-5=\sqrt[]{13} \\ x=\sqrt[]{13}+5 \\ or \\ x-5=-\sqrt[]{13} \\ x=-\sqrt[]{13}+5 \end{gathered}

User Quyen Nguyen Tuan
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